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worldoptimizer/createSequence.js

Created June 22, 2022 10:05
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  1. worldoptimizer created this gist Jun 22, 2022.
    81 changes: 81 additions & 0 deletions createSequence.js
    View file
    Original file line number Diff line number Diff line change
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    /**
    * This function creates another function that can be used to loop through a set of steps.
    * This could be useful, for example, in creating animations or a set of instructions that need to be followed in order.
    *
    * @param {Array} arr - The array of steps to be looped through
    * @param {number} i - The index to start at
    * @param {function} callback - The function to be called on each step
    * @param {string} key - The key to use for the object
    * @returns {function} - A function that can be used to loop through the steps
    */
    function createSequence(arr, i, callback, key) {
    i = i || 0;
    const steps = [];
    arr.forEach(step => {
    if (Array.isArray(step)) {
    for (let j = 0; j < step[0]; j++) {
    steps.push(step[1]);
    }
    } else {
    steps.push(step);
    }
    });

    return function(n) {
    n = n == undefined ? 0 : n;
    if (typeof n === "string") i = n = parseInt(n);

    if (i >= steps.length) i = i % steps.length;
    if (i < 0) i = steps.length + (i % steps.length);

    let step = steps[i];
    i += n;

    if (typeof step === "function") step = step();

    switch (typeof callback) {
    case "function":
    callback(step);
    break;

    case "object":
    if (key) callback[key] = step;
    break;
    }
    return step;
    };
    }

    // Simple usage

    // create a sequence of months
    const months = createSequence(["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]);

    // calling
    console.log(months()) //gives you the current month
    console.log(months(1)) //gives you the current month and advances one

    // create a sequence of letters and set the value of the object's "letter" property to the current letter
    const myObject = {};
    const letterSequence = createSequence(["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"], 0, myObject, "letter");

    // calling
    console.log(letterSequence(), myObject) //gives you the current letter, also sets it as myObject.letter
    console.log(letterSequence(1), myObject) //gives you the current letter and advances one, also sets it as myObject.letter


    // create a sequence of numbers and set call a callback on it
    const numberSequence = createSequence([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 0, function(step) {
    console.log("Do something with step like multiply by 5 = ", step * 5);
    });

    // calling
    console.log(numberSequence()) //gives you the current number, calls callback with it
    console.log(numberSequence(1)) //gives you the current number and advances one, calls callback with it

    // demo of a sequence with a number on the times a item should be inserted
    const repeatDemoSequence = createSequence([[2,'Hello'], [4,'World']]);

    // calling repeatDemoSequence(1) repeatedly would output
    // "Hello", "Hello", "World", "World", "World", "World"